Khorne is generally the most powerful, though Nurgle also becomes strong regularly. According to the 3.5 codex, though Slaanesh could challenge Khorne briefly, the very nature of its power would cause it to burn out long before Khorne.
There are four Chaos Gods: wrathful Khorne, devious Tzeentch, pestilential Nurgle and cruel Slaanesh. All are jealous and prideful deities, each believing himself destined to be the supreme ruler of all existence.
Khaos is one of the most powerful divinities that ever lived. Their power is equal to that of God, with Khaos being His shadow, the chaotic shadow of God.
Slaanesh is the Chaos God of pain and lust. He is the weakest of the four chaos gods and the fastest fighter from his speedster movement.
Slaanesh is the youngest of the Chaos Gods, birthed by the fall of the ancient empire of the Aeldari. However, there is much more to learn the deeper you delve into the lore of these cataclysmic events.
KHAOS (Chaos) was the first of the primordial gods (protogenoi) to emerge at the dawn of creation. She was followed in quick succession by Gaia (Gaea, Earth), Tartaros (the Pit Below) and Eros (Procreation). Khaos was the lower atmosphere which surrounds the earth--both the invisible air and the gloom of fog and mist.
So while Chaos is infinitely more powerful than Zeus, that is not to diminish the power of the “King of the Gods,” who could be called the most powerful of the corporeal beings in the universe.
The Primordials were the most powerful gods, most of them stronger than all the Olympians like Zeus and the Titans like Cronos, the Jötnar including Starkaðr and the Norse Gods like Odin. Chaos and Ymir was the most powerful of them all.
Malal-Malice. Way back in the early days of Warhammer there was a 5th Chaos god. The god was named Malal and they were the god of Anarchy. One particular trait of Malal was that he particular hated all of the other Chaos gods and loved to wage war on them.
Edward Lorenz was the father of "chaos theory," also known as the "butterfly effect." He explained how something as small as the flutter of a butterfly's wings could lead to a big change elsewhere in the world, like a tornado.
Okada became the leader of Chaos after Nakamura's departure from New Japan and succeeded Hiroshi Tanahashi as the promotion's "ace," or top star. Rocky Romero, another member of Chaos, won the IWGP Junior Heavyweight Tag Team Championship a record eight times.
Father of Chaos Theory, Edward Lorenz, Dies.
The Orks can also be considered to be the most successful and powerful in Warhammer 40K due to their partial immunity to chaos, ability to reproduce quickly, and ever-growing strength when facing powerful threats.
Slaanesh is often referred to as a "he," with the masculine gender, though in fact, like all the entities composed of magical energy called the Chaos Gods, it in fact has no true gender, and Slaanesh prefers a far more androgynous appearance than his fellow Ruinous Powers.
Khorne is the mightiest of the Chaos Gods. Every act of violence and killing empowers him, regardless of whether it was committed by his followers, his enemies or even those ignorant of his existence.
The first god to appear in Greek myth is Chaos (or Kaos), who represented the void. He was shortly thereafter he was joined by Gaia, who both was and represented the Earth. Chaos would give birth to two children, the Nyx (Night} and Erebus (Darkness). They in turn would give birth to Aether (Light) and Hemera (Day).
Oberon (The Primordials)
Hesiod, in his Theogony, considers the first beings (after Chaos) to be Gaia, Tartarus, Eros, Erebus, Hemera and Nyx. Gaia and Uranus in turn gave birth to the Titans, and the Cyclopes.
Chaos, (Greek: “Abyss”) in early Greek cosmology, either the primeval emptiness of the universe before things came into being or the abyss of Tartarus, the underworld. Both concepts occur in the Theogony of Hesiod. First there was Chaos in Hesiod's system, then Gaea and Eros (Earth and Desire).
Numbered amongst the most powerful of the Chaos Gods are Khorne, the god of warfare, rage and murder, Nurgle, the god of disease, despair and decay, Tzeentch, the god of change and sorcery and Slaanesh, the god of pleasure and excess.
In Greek mythology, Chaos comes from the Greek word χάος and Eris, the God of Chaos, was known among the other Greek gods for her short temper, moodiness, and bloodlust. She loved carnage and chilling with her brother, God of War, Ares.
In Hesiod's Theogony, Nyx is born of Chaos. With Erebus (Darkness), Nyx gives birth to Aether (Brightness) and Hemera (Day).
Still a third group, grouped around the ritual worship of the mythological poet Orpheus, would devise an even more unique cosmogony. According to them, together with Aether and Erebus, Chaos was one of the three sons of Chronos. She was a master artist who managed to shape an egg from the formless Aether.
The oldest and first of the chaos god is Khorne, this is said repeatedly in the Liber Chaotica which is our best in universe canon understanding of how the forces of chaos function.